Intraluminal, intracavity, intravascular, and intracardiac treatments and diagnosis of medical conditions utilizing minimally invasive procedures are effective tools in many areas of medical practice. These procedures are typically performed using diagnostic and interventional catheters that are inserted percutaneously into the arterial network and traversed through the vascular system to the site of interest. The diagnostic catheter may have imaging capability, typically an ultrasound imaging device, which is used to locate and diagnose a diseased portion of the body, such as a stenosed region of an artery. For example, U.S. Pat. No. 5,368,035, issued to Hamm et al., the disclosure of which is incorporated herein by reference, describes a catheter having an intravascular ultrasound imaging transducer.
Currently, there exists no indicated intravascular imaging method for the neurovasculature. When evaluating a proposed intravascular imaging device for the neurovasculature, the procedure steps for coronary interventions serve as baseline. Typically, for cardiovascular intervention, the use of the imaging device alternates with the use of the treatment device, i.e., a clinician would insert the imaging device to diagnose the area of interest, and then remove the imaging device to insert the appropriate treatment device. Applied to the neurovascular system this may be particularly undesirable due to time considerations in the treatment of strokes and/or intravascular aneurysms. In such cases, it may be desirable to provide simultaneous and/or real-time intra-lumen imaging of a patient's vasculature.
In the case of a stroke caused by embolus, it may be beneficial for the clinician to determine the nature of the embolus in order to plan necessary intervention. The embolus may come in two forms, hard plaque or soft thrombus, and different treatments may be used for each. For soft thrombus, drug treatment may be preferred, since it is a more conservative treatment, but such a treatment may be ineffective for hard plaque, which may require more aggressive treatments such as stent placement. The ability to make a quick assessment benefits the patient by receiving the most applicable intervention as soon as possible.
In the case of an aneurysm, the ability to characterize the aneurysm accurately is very important, particularly for embolic coiling procedures. The diameter of the neck of the aneurysm, the diameter of the aneurysm itself, the density of the sac thrombus, and the patency of the parent artery are all important items of data when planning intervention. The ability to determine and/or confirm these items of data real time may provide a factor of safety when planning the required intervention. For example, the embolic coils originally chosen for treatment based on angiograms may have to be modified based on findings that the aneurysm neck is larger or smaller than anticipated. Accordingly, an improved intravascular intervention device would be desirable.